City Birds Are Changing Their Songs Due to Urban Noise

ADRIAN FLORIDO, HOST: Take a listen to this robin. (SOUNDBITE OF ROBIN TWEETING) FLORIDO: Does it sound a little weird to you? (SOUNDBITE OF ROBIN TWEETING) FLORIDO: No? Well, what about compared to this robin? (SOUNDBITE OF ROBIN TWEETING) FLORIDO: These are two different robins - the first in a city, the second out in nature. New research shows that some city birds are actually changing their songs. MONIKA JABLONSZKY: Animals have to adapt to be able to live in cities. FLORIDO: This is Monika Jablonszky from the Centre for Ecological Research in Hungary. JABLONSZKY: It always starts with the simple sax and that (imitating rhythm). FLORIDO: She's been studying how and why these city dwellers are changing their songs. JABLONSZKY: The traffic noise is the most common. Not only the noise, but other urban phenomenon also influence songs, like the different physical structure of the environment because of the buildings. FLORIDO: Birds sing as part of the mating process or to mark territory. But what good does it do if your fellow avians can't hear you over the ruckus of the city? JABLONSZKY: So the birds try to sing higher. FLORIDO: They try to sing higher. Some birds change the frequency of their songs, others change individual notes. (SOUNDBITE OF BIRD TWEETING) FLORIDO: But most city birds, Jablonszky says, they actually don't change their songs at all. JABLONSZKY: And I think it's a good thing because it means that the birds, regardless of their song or the characteristic of their song, are able to live in cities. FLORIDO: Even so, she thinks it is important to know which birds are forced to adapt. To know how what we build affects the natural world around us, sometimes you just have to stop and listen. (SOUNDBITE OF BIRDS TWEETING)